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What I learned today: heavy handed postprocessing.

JonPB

New member
Today I learned that I need to be heavy handed when post processing my film scans. It is probably old hat to most people here, but I'd been in digital-mode for a long time before turning back to film this year. In retrospect, the lesson is obvious: my scanner records 7200 dpi, but only resolves about 3900 dpi, so there's a lot of mush there to work through. Lightroom simply won't apply strong enough settings to the files because the kind of setting that works for an oversampled film scan would do unspeakable things to an image from a digital camera. Photoshop Elements works passably well with multiple sharpening runs (e.g., sharpen, downsize, sharpen, return to Lightroom), but RawTherapee takes the cake for me with its "Contrast by Detail Levels" system that is like King Kong when compared to the poodle that is Clarity.

Without working too hard at finding the best results, I now feel like my film images (35mm) only give up a slight edge in high resolution acutance to 16 mpix cameras and nothing in terms of noise/grain at ISO 100--which means I can move on from my flirtation with getting a new digital toy. (Unless that new toy is a scanner that gets all the detail out of the film--which would make an M240 kit look affordable.) Sorry that I don't have any good images to share; there's nothing I see in my library that matches up well enough, digital to film, to use to convince someone else of my conclusion. But for anyone out there in internetland who wants to get more crispness and detail out of their film scans, I highly recommend trying settings that go against every digital-camera-calibrated instinct that you may have.

Cheers,
Jon
 

250swb

Member
I know what you mean, but I wouldn't call it heavy handed, just doing what is needed. I tend to sharpen in two stages, a medium sharpening to give me something to work on, and confirm the image will be sharp, then a final sharpening at the sizing stage which really crisps the grain up.

I haven't used RawTherapee but if I get your drift I use something similar, Silver Efex Pro, and in it is a 'Structure' tool that is equivalent to 'Clarity' in ACR. Except it isn't, because you can adjust the Highlight, Mid Tone and Shadow 'structure' separately and it has a setting for 'Fine Structure' which is the thing that works so well on grain and small detail.

Just a few simple tools can transform a scanned image but I think for many people its knowing where to find them and discovering how to use them. It doesn't have to be complicated.

Steve
 

JonPB

New member
You're quite right, Steve. It is what is needed--I'm just excited from finding this stuff in my negatives. Might have to go back and rescan a few. :)

The luminosity-dependent local contrast of Silver Efex Pro sounds worth looking into. With RawTherapee (which is open, free software if you want to give it a shot), there are settings for "widths" of contrast to effect--which I've found to be great for removing noise without low-frequency artifacts as well as for sharpening.

Anyhow, since my initial enthusiasm for many levels and kinds of sharpening has been tempered by the noise that such treatment produces--much like it was with haloing when working on purely digital images--I've set up a decent preset for myself. Here's an example:


RawTherapee by jpb@pdx, on Flickr. (This is equivalent to 1:1 magnification of an 18 mpix sensor.)

Of course, as always, it is a work in progress. But I had been feeling more pressure to go back to digital to enable large prints... now, they may look like film prints, but I'm not worried about losing out on detail to a 16 mpix camera.

Cheers,
Jon
 
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